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How We Nearly Lost the Discovery Shuttle

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Re: How We Nearly Lost the Discovery Shuttle

#41

Post by DeepDuh »

btilly wrote: post #26
vladd wrote: post #13

Earlier quoted context omitted.

Actually the space shuttle is the safest launch vehicle to date. From the ones that have at least 100 launches (in order to be able to properly compute stats for them), here are their failure rates as taken from http://www.ontonix.com/Blog/Outliers_-_understanding_Nature_... : 2% US Space Shuttle 5% R-7 (Russian Soyuz) 5% Ariane 1-4 (European) 6% Tsyklon (Russian) 7% Kosmos (Russian) 10% Thor/Delta/N1/N2/H1 (US) 11%…

I was involved in a similar discussion a couple of weeks ago. I was looking at the same figures you were and complimented the space shuttle because of it. I was wrong, and you're making the mistake that I did. Namely confusing reliability and safety. A reliable rocket is one that successfully does what it is supposed to. A safe rocket is one that doesn't kill people. The US space shuttle has proven to be more reliabl…

These are the moments when I love HN. Some hard facts here, thanks for explaining!

Re: How We Nearly Lost the Discovery Shuttle

#42

Post by jlgreco »

btilly wrote: post #26
vladd wrote: post #13

Earlier quoted context omitted.

Actually the space shuttle is the safest launch vehicle to date. From the ones that have at least 100 launches (in order to be able to properly compute stats for them), here are their failure rates as taken from http://www.ontonix.com/Blog/Outliers_-_understanding_Nature_... : 2% US Space Shuttle 5% R-7 (Russian Soyuz) 5% Ariane 1-4 (European) 6% Tsyklon (Russian) 7% Kosmos (Russian) 10% Thor/Delta/N1/N2/H1 (US) 11%…

I was involved in a similar discussion a couple of weeks ago. I was looking at the same figures you were and complimented the space shuttle because of it. I was wrong, and you're making the mistake that I did. Namely confusing reliability and safety. A reliable rocket is one that successfully does what it is supposed to. A safe rocket is one that doesn't kill people. The US space shuttle has proven to be more reliabl…

The video of T-10-1 is stunning:

http://www.youtube.com/watch?v=UyFF4cpMVag

That the people on that rocket escaped with "bruises" is amazing.

Re: How We Nearly Lost the Discovery Shuttle

#43

Post by mleonhard »

maayank wrote: post #40

I posted some days ago an appendix by Feynman in the Challenger report, "Appendix F - Personal observations on the reliability of the Shuttle"[1] for those interested. Also, half of "Why do you care what people think?" is about his experience investigating the safety of the shuttle. [1] http://news.ycombinator.com/item?id=4371024

I like his point about how bottom-up development is superior to top-down development.

Re: How We Nearly Lost the Discovery Shuttle

#44

Post by maayank »

mleonhard wrote: post #43
maayank wrote: post #40

I posted some days ago an appendix by Feynman in the Challenger report, "Appendix F - Personal observations on the reliability of the Shuttle"[1] for those interested. Also, half of "Why do you care what people think?" is about his experience investigating the safety of the shuttle. [1] http://news.ycombinator.com/item?id=4371024

I like his point about how bottom-up development is superior to top-down development.

A lot of what he said regarding reliability figures and testing plans reasoning resonated with my experience in (software engineering) projects and made me think how his remarks are applicable to software development.

Note to people who didn't read the appendix - he touches specifically software development in the latter part of his note.

Re: How We Nearly Lost the Discovery Shuttle

#45

Post by rdl »

The lesson I take from this is that the Shuttle should have been killed on the drawing board, never flown. It's a hideously complex design with no real advantages over expendable or re-usable rockets. It might have made sense as part of a tens of trillions of dollar integrated infrastructure plan (as originally proposed in the 1970s), but once those elements were killed, zombie/frankenstein shuttle wasn't the right answer.

NASA could have focused more on great science programs (like the Mars rovers, unmanned deep space probes, planetary science -- think of what they could accomplish with even 50% of the current overall NASA budget), military and government launch could have continued with ICBM-derived rockets, and private space could have gotten an earlier start.

Re: How We Nearly Lost the Discovery Shuttle

#46

Post by Someone »

btilly wrote: post #26
vladd wrote: post #13

Earlier quoted context omitted.

Actually the space shuttle is the safest launch vehicle to date. From the ones that have at least 100 launches (in order to be able to properly compute stats for them), here are their failure rates as taken from http://www.ontonix.com/Blog/Outliers_-_understanding_Nature_... : 2% US Space Shuttle 5% R-7 (Russian Soyuz) 5% Ariane 1-4 (European) 6% Tsyklon (Russian) 7% Kosmos (Russian) 10% Thor/Delta/N1/N2/H1 (US) 11%…

I was involved in a similar discussion a couple of weeks ago. I was looking at the same figures you were and complimented the space shuttle because of it. I was wrong, and you're making the mistake that I did. Namely confusing reliability and safety. A reliable rocket is one that successfully does what it is supposed to. A safe rocket is one that doesn't kill people. The US space shuttle has proven to be more reliabl…

I think it is reasonable to say the shuttle was supposed to "get into space on the day it was planned to launch".

I do not have data on it, but using that yardstick or even the more lenient "get into space within a month of the planned date", I think it was not very reliable. I also have the impression (but again: I do not have data) that the Soyuz is way more reliable in that respect.

Re: How We Nearly Lost the Discovery Shuttle

#47

Post by wissler »

rdl wrote: post #45

The lesson I take from this is that the Shuttle should have been killed on the drawing board, never flown. It's a hideously complex design with no real advantages over expendable or re-usable rockets. It might have made sense as part of a tens of trillions of dollar integrated infrastructure plan (as originally proposed in the 1970s), but once those elements were killed, zombie/frankenstein shuttle wasn't the right a…

> The lesson I take from this is that the Shuttle should have been killed on the drawing board, never flown.

Exactly, yes. The design should have been revised until they weren't pushing safety margins so hard. Of course, that would have been an engineer-led approach, which is the opposite approach from the one they used.

Re: How We Nearly Lost the Discovery Shuttle

#49

Post by tjic »

gus_massa wrote: post #39
vladd wrote: post #13

Earlier quoted context omitted.

Actually the space shuttle is the safest launch vehicle to date. From the ones that have at least 100 launches (in order to be able to properly compute stats for them), here are their failure rates as taken from http://www.ontonix.com/Blog/Outliers_-_understanding_Nature_... : 2% US Space Shuttle 5% R-7 (Russian Soyuz) 5% Ariane 1-4 (European) 6% Tsyklon (Russian) 7% Kosmos (Russian) 10% Thor/Delta/N1/N2/H1 (US) 11%…

The problem is that in the list there are manned and unmanned rocket mixed. For example, the Ariane rockets are still unmanned, so if they lost one it is only an insurance problem. The Soyuz had manned and unmanned mission. But all the missions of the Shuttle were manned, so each time they had a big problem they had casualties. It would be interesting to see that includes only the manned missions.

This is a very good point for a reason that you don't call out:

Man-rated systems are DESIGNED to be much safer. The trade-off involving dollars is entirely different. You can't criticize a non-man-rated system for blowing up any more than you can criticize a UDP packet for not getting through: that trade-off was engineered in.

Re: How We Nearly Lost the Discovery Shuttle

#50

Post by ak217 »

K2h wrote: post #6

This is an outstanding post that shows first hand what life as an engineer is like. It is often very hard to truly come to a conclusion that is 100% correct, even given what seems like infinite resources to do testing and analysis. The big take away from this is what it means to be a good engineer: to be able to bow your head, and admit you were wrong despite all prior evidence. outstanding!

> what it means to be a good engineer: to be able to bow your head

No, I think being a good engineer means building good things. When the things get sufficiently complex, that starts to require control of your ego (what you described), being a good scientist/investigator, organizational skills, etc.

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